Penninsular diesel supplied the intercooler it is serviceable. It is the same one they have been running on their 6.5 diesels for years. It will get raw lake water through it. This boat will use a closed cooling system with a Penninsular diesel heat exchanger and oil cooler. Raw water will run through the oil cooler then the heat exchanger next the intercooler followed by the manifolds and up pipes exiting out the exhaust down pipe and through the OE exhaust ports.